Nearly 22,000 children are hospitalized annually for complications of insulin dependent diabetes mellitus (IDDM). Diabetic ketoacidosis (DKA) is a life threatening condition and is the number one reason for IDDM related admissions. Cerebral edema occurs in 1-3% of pediatric DKA episodes and accounts for 30 - 90% of DKA deaths. Although several studies document cerebral edema in children with DKA, the cause of cerebral edema is unknown. The lack of understanding of the pathophysiology of cerebral edema leaves children with IDDM at risk for death or permanent disability, and health care providers without the necessary knowledge to prevent this complication. Epidemiologic data suggest an association between cerebral ischemia and cerebral edema in pediatric DKA. However, limited clinical studies document cerebral hyperemia NOT cerebral ischemia. Therefore, the overall goals of this study are to characterize cerebrovascular changes in children critically ill with DKA, and to determine the relationship between laboratory markers, cerebrovascular changes and the presence or absence of cerebral edema.To do this, we propose three specific aims: 1)To examine the relationship between cerebral hyperemia and cerebral edema in children with critical and severe DKA, 2) To determine the incidence of impaired cerebral autoregulation in critical and severe DKA and 3) To explore the relationship between potential clinical and laboratory predictors and cerebral hyperemia and cerebral edema in critical and severe DKA. The findings of this study will lead to: 1) a greater understanding of the pathophysiology of DKA related cerebral edema, 2) the innovative use of existing methodologies to examine cerebrovascular changes in pediatric DKA (new scientific area), and ultimately through further study, 3) the development of a clinically useful scoring system and screening program that identifies children at risk for cerebral edema, and 4) the identification of management strategies needed to prevent cerebral edema. [unreadable] [unreadable]